Liquid vs. Bar in Dr. Bronner’s Pure-Castile Soap

The liquid came first – peppermint to be exact. Bar soap meandered in a few decades later. While there are hardliners in both camps, the difference between liquid and bar is mostly a matter of personal preference. However, there are some differences between the two.

Here are the ingredients side by side for the Baby Unscented Pure-Castile Soap. I chose our simplest soap, which lacks any essential oils, so that the differences are easier to see.

Differences explained:

  • Liquid contains more water.
    • Why: There is just enough water in the liquid soaps to keep them liquid. Any less water and the soap begins to solidify. To test this, leave the cap off your bottle for a day, and you’ll notice the soap’s starting to gel. You can reliquify it with a bit of water. (The thickness, or thinness, of the soap is not due to high water content, but to the consistency of the various oils.)
    • Effect on Performance: None
  • Liquid uses potassium hydroxide to saponify oils; bar uses sodium hydroxide.
    • Why: Hardness – sodium hydroxide produces a harder soap than potassium hydroxide. The purpose of these strong alkalis is to blast apart the oil molecules, separating the glycerin from the fatty acids. The fatty acids then reattach to the sodium or potassium ion, leaving the glycerin and water (hydroxide) free-floating. (Just a sidenote – soap cannot be made any other way. None of these alkalis are left in the soap. Check out the link at the bottom about soapmaking.)
    • Effect on Performance: None
  • Bar contains palm oil, in addition to coconut oil.
    • Why: Palm oil hardens more than coconut oil. Coconut oil, even in its solid state, is mushy, and it melts at 76° F.
    • Effect on Performance: Bar soap is slightly more moisturizing. Palm oil contains stearic acid, which some people find to be less drying than the lauric acid found in coconut oils.
  • Bar contains salt (NaCl – sodium chloride or table salt).
    • Why: Also serves as a hardener.
    • Effect on Performance: Bar soap is slightly more moisturizing. Since our bodies are slightly salty, salt water is gentler on our skin than pure water. Salty soap is, too.

Other Differences in Formulation:

  • How the Hemp and Jojoba oils are added:
    • In the liquid soaps, the hemp and jojoba oils are saponified, i.e. turned into soap, along with the coconut and olive oils. However, in the bar soaps, these two oils are added unaltered after the saponification process. This is called “superfatting” the soaps. A while back my brothers tried superfatting the liquids with the hemp and jojoba oils, but found that the oils separated out and floated to the top.
    • Effect on Performance: Bar soaps produce a creamier lather and are slightly more moisturizing.
  • Amount of Essential oils:
    • This is only relevant to the scented soaps (everything except the Baby Unscented). The liquid soap have a higher percentage of the essential oils than do the bar soaps. Once again, the issue at stake is hardness. The bar soaps would soften with that high a concentration of the essential oils.
    • Effect on Performance: This is entirely a matter of personal preference. Those who like an intense whiff of scent, and those who are looking for the specific benefits of the particular essential oils, should opt for the liquids. Those who like a little scent, but not too much, the bar soap would be better.

Differences in usage:
For all body applications, they are entirely interchangeable – from washing face, hair, or body, or shaving. For around the house purposes, you would need to take the extra step of dissolving the bar soaps in water before using them in a spray bottle solution, but they are equally effective. Also, the bar soap can be grated to achieve a kind of powdered soap for laundry, although the liquid works just as well.

Volume of actual soap:
I don’t know how to de-math this, but people who put together their own recipes for cleaners might want to know this. Bar soaps are 5% water; liquids are 61%. The chemistry is a little different for both, but considering that a bar of soap weighs 5 oz, and thus 4.75 oz of it is soap, you would need 12.18 ounces (a little over 1 ½ c.) of liquid soap to equal the soap content of a 5 oz bar. Doing the math the other way, 1 cup of liquid soap equals approximately 2/3 of a bar (or 3.64 oz.) of Dr. B’s bar soap.

Bottom Line:
The Dr. Bronner’s Pure-Castile Bar and Pure-Castile Liquid soaps are interchangeable. However, the bars are slightly more moisturizing. The liquids are slightly more scented.

If you want more info on the process of soapmaking, check out this article, Making the Best Soap. And here’s a video tour of our Liquid Soap Production Factory.

If you have any other questions about what is in the soap and why or where it is sourced and why or anything else, let me know!

306 thoughts on “Liquid vs. Bar in Dr. Bronner’s Pure-Castile Soap

    • Hi Deb – Although we do not yet have a gluten free certification, all of our products – soaps, balms, lotions, shave gels, hair care and coconut oils – are gluten free and we do not process gluten in our factory.

  1. Hi there! I was wondering if someone could tell me if the bars of soap float in water?
    Thanks so much!

    • Hi Shawna – Our bar soaps do not float because they are denser than water. Soap that floats has air whipped into it, making it less dense.

  2. Hi Lisa, I want to know the expiry date for dr bronner liquid castile soap 946 ml.
    Lot code printed on the bottle is 18130 5708. Please reply when is expiry date.

    • Hi Prabu – The expiration date is 3 years from manufacture – in this case May 10, 2018 – but I find that if the soap is kept indoors in a dark place it can last much, much longer. The scent might fade over time, though.

  3. I’ve been making my own laundry detergent that uses bar soap. I’ve not been able to find Dr. Bronner’s bar soap locally, but have found the liquid soap. Using the conversion formula above would tell me how much liquid soap to use. Can you think of any other reason that bar soap would be better? Or should I not use the liquid?

    • Hi Jim – The bar soap, Castile soap and Sal Suds all work equally well as laundry detergents. It is simply a matter of personal preference. If you give the Castile soap a try, use 1/4-1/3 c. of soap per large load in a top loading machine or half that for an HE machine. Sal Suds is more concentrated so 2T is all you need (again, half for HE). With either one, you can add 1/2 c. (1/4 c. for HE) of baking soda for extra whitening, brightening, softening, and deodorizing.

  4. Can the bar soap be used on the face? And is it effective on the face like the liquid ?

    • Hi Monique – Yes, absolutely! It is slightly more moisturizing than the liquid Castile soap, so it’s simply a matter of personal preference.

  5. The bar soaps were my entry to the world of Dr. Bronner’s and I absolutely love them for body and face washing. I have long been wondering if they’re just as good as the originals — glad to find this post to verify that they are! (Of course there’s also a bottle of the liquid soap in the house for everything else).

  6. How do you dilute the bar soap to wash your face? I use a spin brush to wash my face. I tried to just wet the spin brush and scrub it a little on the bar and then wash my face, but it think it wasn’t diluted enough because my skin was very red and irritated the next morning.

    • Hi Lani- If both the spin brush and the soap are new, use just one of them for a couple of weeks to see if you can identify whether it’s the brush or the soap irritating your skin. There’s often a transition period for skin when trying out a new skin regimen. I agree, you just need a little soap. Wetting the bar and lightly tapping it on the brush would be sufficient. You might try adding a little extra moisturizer during the transition period as well.

  7. Does it take some time for your face to adjust to the bar soap? I am 50 and have a pretty good regime going now, but I would much prefer to go natural/vegan and I want to something that I can use for my hair, face, and body. I tried the almond bar soap once and my face instantly broke out. Should I keep trying it for a certain amount of time or try something else?

    • Hi Sara – It can take up to two weeks for skin to adjust to a new regimen. I know that time period can be challenging. The almond is a mild scent and the bar more moisturizing than the liquid Castile soap, making it good for dryer skin. Continue to moisturize and exfoliate gently. Let me know how it goes.

  8. So there really shouldn’t be a difference in how your skin reacts to the soap?

    • Hi Elizabeth – The bar soap is more moisturizing, but it is primarily personal preference.

  9. Hi could you tell me where the tocopherol has been derived from used in the naked lip balm thank you

    • Hi Shelly – The tocopherols we use are from non-GMO sunflower oil.

    • Thank you. I keep getting emails saying subscribe to you. Have I subscribed ok? Every time I click it sends another one. Not sure I’m doing something wrong ha ha x

    • Hi Shelly – Great, thanks for subscribing! It looks like you’re all set. When someone subscribes, there is a follow-up email to confirm you’re a real person and really do want to subscribe. Maybe that’s what was going on. From now on, you’ll receive an email when there’s a new blog post.

    • Hi Lisa I just wanted to say thank you for making such an amazing lip balm. Since October my lips have been dry chapped cracked and inflamed all around my mouth nothing would get rid of it. After 2 days of using your lip balm it’s completely gone and my lips are maItback to normal and feel great fantastic thank you so much I will be ordering lots more 😊 xx

    • Hi Shelly – That’s great to hear! Our family goes through it pretty quick this time of year as well.

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